1,289 research outputs found
Low-momentum interactions with Brown-Rho-Ericson scalings and the density dependence of the nuclear symmetry energy
We have calculated the nuclear symmetry energy up to
densities of with the effects from the Brown-Rho (BR) and
Ericson scalings for the in-medium mesons included. Using the
low-momentum interaction with and without such scalings, the equations of state
(EOS) of symmetric and asymmetric nuclear matter have been calculated using a
ring-diagarm formalism where the particle-particle-hole-hole ring diagrams are
included to all orders. The EOS for symmetric nuclear matter and neutron matter
obtained with linear BR scaling are both overly stiff compared with the
empirical constraints of Danielewicz {\it et al.} \cite{daniel02}. In contrast,
satisfactory results are obtained by either using the nonlinear Ericson scaling
or by adding a Skyrme-type three-nucleon force (TNF) to the unscaled
interaction.
Our results for obtained with the nonlinear Ericson scaling
are in good agreement with the empirical values of Tsang {\it et al.}
\cite{tsang09} and Li {\it et al.} \cite{li05}, while those with TNF are
slightly below these values. For densities below the nuclear saturation density
, the results of the above calculations are nearly equivalent to each
other and all in satisfactory agreement with the empirical values.Comment: 7 pages, 6 figure
Microbial ecology of Thiobacillus ferrooxidans
FINAL TECHNICAL REPORT
TO
U.S. DEPARTMENT OF THE INTERIOR
Geological Survey
Washington. D.C.The contents of this report were developed in part under a grant from
the Department of the Interior, U.S. Geological Survey. Grant number 14-08-0001-61313
Design an Intelligent System to automatically Tutor the Method for Solving Problems
Nowadays, intelligent systems have been applied in many real-word domains. The Intelligent chatbot is an intelligent system, it can interact with the human to tutor how to work some activities. In this work, we design an architecture to build an intelligent chatbot, which can tutor to solve problems, and construct scripts for automatically tutoring. The knowledge base of the intelligent tutoring chatbot is designed by using the requirements of an Intelligent Problem Solver. It is the combination between the knowledge model of relations and operators, and the structures of hint questions and sample problems, which are practical cases. Based on the knowledge base and tutoring scripts, a tutoring engine is designed. The tutoring chatbot plays as an instructor for solving real-world problems. It simulates the working of the instructor to tutor the user for solving problems. By utilizing the knowledge base and reasoning, the architecture of the intelligent chatbot are emerging to apply in the real-world. It is used to build an intelligent chatbot to support the learning of high-school mathematics and a consultant system in public administration. The experimental results show the effectiveness of the proposed method in comparison with the existing systems
Type-B Goldstone modes and a logarithmic spiral in the staggered ferromagnetic spin-orbital model
It is found that the staggered ferromagnetic spin-orbital model
accommodates highly degenerate ground states arising from spontaneous symmetry
breaking with type-B Goldstone modes. The spontaneous symmetry breaking pattern
is ,
with three type-B Goldstone modes. An abstract fractal underlies the ground
state subspace with the fractal dimension identified with the number of type-B
Goldstone modes. This connection is established by evaluating the entanglement
entropy, which exhibits a universal finite system-size scaling behaviour. The
latter in turn implies that the entanglement entropy scales logarithmically
with the block size in the thermodynamic limit. In addition, the ground state
degeneracies, depending on the boundary conditions adopted, constitute the two
Fibonacci-Lucas sequences. In the limit of large system size their asymptotic
forms become a self-similar logarithmic spiral. As a result, the model has a
non-zero residual entropy , where .Comment: 16 pages, 5 figures, 1 table. arXiv admin note: substantial text
overlap with arXiv:2302.1312
Goldstone modes and the golden spiral in the ferromagnetic spin-1 biquadratic model
Ferromagnetic ground states have often been overlooked in comparison to
seemingly more interesting antiferromagnetic ground states. However, both the
physical and mathematical structure of ferromagnetic ground states are
particularly rich. We show that the highly degenerate and highly entangled
ground states of the ferromagnetic spin-1 biquadratic model are scale
invariant, originating from spontaneous symmetry breaking from to
with two type-B Goldstone modes. The ground state
degeneracies are characterized as the Fibonacci-Lucas sequences -- an ancient
mathematical gem, under open and periodic boundary conditions, with the
residual entropy being non-zero. This implies that the ground state
degeneracies for this model are asymptotically the golden spiral. In addition,
sequences of degenerate ground states generated from highest and generalized
highest weight states are constructed to establish that the entanglement
entropy scales logarithmically with the block size in the thermodynamic limit,
with the prefactor being half the number of type-B Goldstone modes. The latter
in turn is identified to be the fractal dimension.Comment: 20 pages, 3 figures,1 table, additional references to earlier related
work adde
A Survey of z ~ 6 Quasars in the Sloan Digital Sky Survey Deep Stripe. II. Discovery of Six Quasars at z AB>21
We present the discovery of six new quasars at z ~ 6 selected from the Sloan Digital Sky Survey (SDSS) southern survey, a deep imaging survey obtained by repeatedly scanning a stripe along the celestial equator. The six quasars are about 2 mag fainter than the luminous z ~ 6 quasars found in the SDSS main survey and 1 mag fainter than the quasars reported in Paper I. Four of them comprise a complete flux-limited sample at 21 < z_(AB) < 21.8 over an effective area of 195 deg^2. The other two quasars are fainter than z_(AB) = 22 and are not part of the complete sample. The quasar luminosity function at z ~ 6 is well described as a single power law Φ(L_(1450))α L^β_(1450) over the luminosity range –28 < M_(1450) < –25. The best-fitting slope β varies from –2.6 to –3.1, depending on the quasar samples used, with a statistical error of 0.3-0.4. About 40% of the quasars discovered in the SDSS southern survey have very narrow Lyα emission lines, which may indicate small black hole masses and high Eddington luminosity ratios, and therefore short black hole growth timescales for these faint quasars at early epochs
Extracting the number of type-B Goldstone modes and the dynamical critical exponent for a type of scale-invariant states
A generic scheme is proposed to perform a finite-entanglement scaling
analysis for scale-invariant states, which appear to be highly degenerate
ground states arising from spontaneous symmetry breaking with type-B Goldstone
modes. This allows us to extract the number of type-B Goldstone modes and the
dynamical critical exponent, in combination with a finite block-size scaling
analysis, from numerical simulations of quantum many-body systems in the
context of tensor network representations. The number of type-B Goldstone modes
is identical to the fractal dimension, thus reflecting an abstract fractal
underlying the ground state subspace. As illustrative examples, we investigate
the spin- Heisenberg ferromagnetic model, the ferromagnetic
model and the spin-orbital model.Comment: 14 pages, 24 figures, 11 table
Clinical and Experimental Applications of NIR-LED Photobiomodulation
This review presents current research on the use of far-red to near-infrared (NIR) light treatment in various in vitro and in vivo models. Low-intensity light therapy, commonly referred to as “photobiomodulation,” uses light in the far-red to near-infrared region of the spectrum (630–1000 nm) and modulates numerous cellular functions. Positive effects of NIR–light-emitting diode (LED) light treatment include acceleration of wound healing, improved recovery from ischemic injury of the heart, and attenuated degeneration of injured optic nerves by improving mitochondrial energy metabolism and production. Various in vitro and in vivo models of mitochondrial dysfunction were treated with a variety of wavelengths of NIR-LED light. These studies were performed to determine the effect of NIR-LED light treatment on physiologic and pathologic processes. NIRLED light treatment stimulates the photoacceptor cytochrome c oxidase, resulting in increased energy metabolism and production. NIR-LED light treatment accelerates wound healing in ischemic rat and murine diabetic wound healing models, attenuates the retinotoxic effects of methanol-derived formic acid in rat models, and attenuates the developmental toxicity of dioxin in chicken embryos. Furthermore, NIR-LED light treatment prevents the development of oral mucositis in pediatric bone marrow transplant patients. The experimental results demonstrate that NIR-LED light treatment stimulates mitochondrial oxidative metabolism in vitro, and accelerates cell and tissue repair in vivo. NIR-LED light represents a novel, noninvasive, therapeutic intervention for the treatment of numerous diseases linked to mitochondrial dysfunction
Energy level statistics for models of coupled single-mode Bose--Einstein condensates
We study the distribution of energy level spacings in two models describing
coupled single-mode Bose-Einstein condensates. Both models have a fixed number
of degrees of freedom, which is small compared to the number of interaction
parameters, and is independent of the dimensionality of the Hilbert space. We
find that the distribution follows a universal Poisson form independent of the
choice of coupling parameters, which is indicative of the integrability of both
models. These results complement those for integrable lattice models where the
number of degrees of freedom increases with increasing dimensionality of the
Hilbert space. Finally, we also show that for one model the inclusion of an
additional interaction which breaks the integrability leads to a non-Poisson
distribution.Comment: 5 pages, 4 figures, revte
SO(1,1) dark energy model and the universe transition
We suggest a scalar model of dark energy with the SO(1,1) symmetry. The model
may be reformulated in terms of a real scalar field and the scale factor
so that the Lagrangian may be decomposed as that of the real quintessence
model plus the negative coupling energy term of to . The existence of
the coupling term leads to a wider range of and overcomes the
problem of negative kinetic energy in the phantom universe model. We propose a
power-law expansion model of univese with time-dependent power, which can
describe the phantom universe and the universe transition from ordinary
acceleration to super acceleration.Comment: 12 pages. submitted to CQ
- …